箍筋约束超高性能混凝土本构模型

为研究箍筋约束超高性能混凝土(ultra-high performance concrete,UHPC)本构模型,统计了箍筋约束UHPC的试验数据,通过回归分析,理论推导,提出了箍筋约束UHPC的应力-应变关系曲线模型及特征点计算方法,并与试验结果、不同箍筋约束混凝土本构模型进行对比分析。结果表明:钢纤维和箍筋可以有效地提高约束UHPC的峰值应力和峰值应变;峰值应力计算结果与试验结果吻合程度较好,而峰值应变以及峰值应力下降至85%和50%所对应应变的计算结果与试验结果吻合程度不够理想;建议的箍筋约束UHPC应力-应变关系曲线模型与试验结果整体吻合程度较好。

Study on the Constitutive Model of Ultra-high Performance Concrete Confined by Stirrups

In order to study the constitutive model of the UHPC confined by stirrups, the experimental results from UHPC confined by stirrups were statistically analyzed. And the calculation methods of stress-strain relationship curves and feature points of UHPC confined by stirrups were proposed by regression analysis and theoretical derivation. Then to analysis by comparing with the experimental results and the other constitutive model of confined concrete. Results show that: both the steel fiber and stirrups can improve the peak stress and the peak strain of the confined UHPC effectively; the constitutive model of the UHPC confined by stirrups reinforcement proposed in this paper agree well with the experimental results overall although some differences exist in peak stress and peak strain of some specimens; in addition it is concluded that the higher the comprehensive constraint coefficient is, the lower the parameter value controling descending branch are, the decline section of the stress-strain relation curve is relatively gentle.